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PostPosted: Fri Jun 04, 2010 11:29 pm 
Devout Dirtbag

Joined: Tue Feb 10, 2009 1:51 am
Posts: 110
Location: An Englishman in Asia
I got terrific help here last time I asked an RD question, so let's see if you can sort this one...

This is NOT about the upper and lower (Philips Hi and Lo) set screws on the rear of the RD body. Nor the "B" tension screw.

It concerns a slotted screw INSIDE the parallelogram. 1992 Deore Lx.

Later Deores do not have it.

Between the parallelogram arms is a tension spring adjusted by a flush-fitting flat-headed screw about 1/4" across. The screw is on the inner (wheel side) arm. The stem of the screw seems to be cam-shaped. It rotates 360 degrees, held in place by a circlip, and has 4 default positions (12 o'clock, 3, 6 and 9 o'clock) to tension the parallelogram spring. The parallelogram arm has a small punch mark, and the screw has a tiny arrowhead, as alignment guides.

I've tried adjusting it to each of the positions it "likes to rest in", (12 o'clock, 3, 6 and 9 o'clock) with no noticeable difference in the feel of the tension at the thumb lever.

I suspect that is why Shimano abandoned it on later Deore RDs.

But it is possible I'm missing something, so if anybody knows how to set this screw properly, please advise. I'm basically asking, how do I set it to the LEAST tension?

My RD works well, but on a recent ten-day tour my right thumb joint was very painful from the effort of changing up the cassette.

Btw. The outer cable is clean, kink free, and well oiled.


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PostPosted: Sat Jun 05, 2010 7:53 am 
retrobike rider
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It does exactly what you describe, tensions the return spring.
It was abandoned as they moved to a standard coil spring and few people used it anyway that didn't really know it was there and Shimano's quest for light action.

I used it to stiffen it more in winter and loosen it for easier shifting in the summer.

I think your problem is the thumb-sifters most have a high friction in them as well that how they work, if you move to something easier on the thumb like gripshift or rapidfire+.
The former you use your whole hand, the latter is a lot lighter action.


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PostPosted: Sat Jun 05, 2010 6:15 pm 
retrobike rider
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Now i'll add this, might tell you what I just said
http://www.retrobike.co.uk/gallery2/mai ... ewsIndex=3


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PostPosted: Sun Jun 06, 2010 8:41 am 
Devout Dirtbag

Joined: Tue Feb 10, 2009 1:51 am
Posts: 110
Location: An Englishman in Asia
Many Thanks "Fluffy Chicken", FULL MARKS!

I found what I needed on the Official Shimano Service leafelet you pointed to in the gallery.

http://www.retrobike.co.uk/gallery2/mai ... ewsIndex=3

It seems there are 3 default settings (not 4 as I thought), and the strongest is with the tiny arrow pointing to the punch mark, so I'll back-pedal it two clicks to set it to the weakest (least tension).

When I removed and cleaned my thumb shifters with paraffin, they work fluidly, with none of the excessive tension I experience when connected up.
So it must be downstream.

I'm happy now that I know how to get the RD tension set to the lowest.

Next I'll double check the cables to make sure I get the easiest up-changing. It +is possible+ a constriction on one of the outer cables is pinching the inner. Just leaning a loaded bike clumsily against a low wall can pinch it.

Thank you very much for your help.

The gallery of Service leaflets is invaluable. I never knew it was there, and many times I've searched for such data on the web.

Any chance you could post the one for the FD651 that's on my 1992 Panasonic? That's front deraileur.

Fascinating to see the little tool they illustrate to set up cantilever brake cables properly.:

http://www.retrobike.co.uk/gallery2/mai ... ewsIndex=1


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PostPosted: Sun Jun 06, 2010 6:12 pm 
retrobike rider
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It could well be the end of the outer casing is crimped or the inner plastic sleeve in the outer-casing has no been properly widened* after cutting/grinding the end.

Or try some teflon coated cables..

Or something else :D

OR take up thumb-gym :lol:


As for the service manuals. Well it went up I think that day or a few days before depending on which set it went up in, I think it was the second :D
http://www.retrobike.co.uk/forum/viewtopic.php?t=103764


* achieved often by using a sharp pencil and sticking in the end and rolling around


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PostPosted: Sun Jun 06, 2010 11:01 pm 
Devout Dirtbag

Joined: Tue Feb 10, 2009 1:51 am
Posts: 110
Location: An Englishman in Asia
Thanks FluffyChicken.

I have set the screw to the lowest tension now. For those who have it, the tiny arrow point directly inwards towards the wheel when in the least tension. You can just about see the end of the spring. When you turn the screw so the marks align, that is the highest tension, and the end of the spring is more visible, lifted up by the cam.

It feels just the same though, so I'll invest in a new cable.

That will have to be Jagwire.

The outer is the original Shimano, now 18 years old, doesn't seem to have any liner at all.

Yes, I'll make sure the inner liner is rounded out and new end caps used.

Thanks agin for your help!


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PostPosted: Mon Jun 07, 2010 11:56 pm 
Devout Dirtbag

Joined: Tue Feb 10, 2009 1:51 am
Posts: 110
Location: An Englishman in Asia
It's worth mentioning:

Whilst I was adjusting the RD tension, I noticed that my FD also has a similar flat-headed spring tension screw (NOT the Hi Lo Philips screws). My model is FD-M651. The screw head nestles flush to the FD body, and (unlike the RD version) has both an Allen key hole and a slot.

The screw head has a tiny arrow, and when this points upwards it is at the Minimum spring tension (you can feel it is far less). It seems to have only 2 default position 180 degrees apart, and I can definitely feel the difference between the Maximum and Minimum at the thumb lever, again, unlike the RD version.


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PostPosted: Tue Jun 08, 2010 7:52 am 
retrobike rider
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I know what it is you are talking about, bottom left of the sheet (from other thread)
http://www.retrobike.co.uk/gallery2/mai ... ewsIndex=3

similar to in this M901 picture (pinched off web)


Attachments:
File comment: tension adjuster front mech
xtr adjuster.jpg
xtr adjuster.jpg [ 31.19 KiB | Viewed 1408 times ]
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PostPosted: Tue Jun 08, 2010 11:44 pm 
Devout Dirtbag

Joined: Tue Feb 10, 2009 1:51 am
Posts: 110
Location: An Englishman in Asia
Yes that picture shows the FD screw clearly, so people will know what we are discussing.

It's the blackish-gray screw with the Allen key and slot.

You can also make out the alignment marks too.

On my model FD-M651 when the marks are aligned together, that is the least tension.

Converesly, and perversely, for the REAR deraileur, that alignment is the Maximum tension.

That is why it would be good to have the correct Shimano data sheet for each different model.

Thanks again for your help.


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PostPosted: Wed Jun 09, 2010 8:54 am 
retrobike rider
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cmjc wrote:
Yes that picture shows the FD screw clearly, so people will know what we are discussing.

It's the blackish-gray screw with the Allen key and slot.

You can also make out the alignment marks too.

On my model FD-M651 when the marks are aligned together, that is the least tension.

Converesly, and perversely, for the REAR deraileur, that alignment is the Maximum tension.

That is why it would be good to have the correct Shimano data sheet for each different model.

Thanks again for your help.


I know t's good to have the correct documents, but that depends on people actually having them and bothering to scan them in ;)

But that mech is near on identical to the M651 mech (Deore DX top pull) . I have both sat next to each other ;) Just the materials are a little different.
Hence why to use the FD-M901 documents.
It would probably be the same picture as they where just relabled documents and this has the alteration of the XTR shifter, hence why they would make one for it.
(The picture above is XTR)


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